The present invention relates to an optical disc drive for recording (writing) and reproducing (reading) data from/upon an orbicular disc under the condition of rotating it, and in particular, it relates to a cooling structure for conducting multi-layer recording with stability.
An optical disc drive is a data storage device for recording data on a disc surface, as well as, for reproducing the data recorded on the disc surface, under the condition of rotating the orbicular disc, i.e., a data recording medium. An electronic part equipped with a semiconductor laser element (or a laser light source) and a laser light receiving portion, etc., to be used as a signal writing/reading means for recording/reproducing the data, is called by an optical pickup, or simple, a pickup. As a disc, being the data recording medium can be listed up the followings: for example, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-R, DVD-RW, DVD-RAM, DVD+R, DVD+RW, BD-ROM, BD-R, BD-RE, etc. And, in general, the optical disc drive is mounted on electronic equipment comprising a central processing unit (CPU) for conducting access control to the optical disc drive and also calculation operation, such as, a personal computer, etc., for example. In case where such electronic equipment is the personal computer, for example, the optical disc drive is called by a half-height optical drive when it is mounted within a desktop-type personal computer, in general, and it is called by a slim-type optical disc drive when it is mounted within a notebook-type personal computer (or a portable personal computer), in general.
At present, for the optical disc drive, it is requested to enlarging the data memory capacity, much more. For the purpose of achieving that, it is necessary to multiply the number of the disc recording layer, but not only one (1) layer, but for dealing with such the multi-layer recording, it is necessary to increase an output of the semiconductor laser element, and as a result thereof, temperature of the laser element increases abruptly. An increase of temperature of the laser element comes into a reason of reducing the lift-time of the element, and this causes lowering of quality of the optical disc drive. In particular, in case of the slim-type optical disc drive, it is smaller than the half-height type optical disc drive, in the volume of housing, and is higher in packing density thereof, and therefore the laser element is exposed in an atmosphere much higher than that.
As a countermeasure for this, for example, in Japanese Patent Laying-Open No. 2005-310192 (2005)<Patent Document 1> is proposed a method for radiating heats generated from the laser element of the optical pickup, effectively, with provision of ventilation openings on a supporting plate (i.e., a unit cover) of the optical pickup within the slim-type optical disc drive, and thereby causing a convection of air passing through the ventilation openings mentioned above, which is generated by a circulating flow of an air accompanying the disc rotation.
However, in the multi-layers recording, since it is impossible to increase the disc rotation number or speed when conducting the one-layer recording, then heat radiation or cooling of the laser element cannot be expected by the air circulating flow caused due to the disc rotation. Accordingly, in the multi-layers recording where a great increase cannot be expected on the disc rotation speed, as well as, the laser output comes to be higher than that when conducting the one-layer recording, it is impossible to dissolve such drawbacks as mentioned above, by the method disclosed in the Japanese Patent Laying-Open No. 2005-310192 (2005)<Patent Document 1>.
In this manner, in such the multi-layers recording wherein a great increase cannot be expected on the disc rotation speed, as well as, the laser output comes to be higher than that when conducting the one-layer recording, since it is impossible to expect the effect of cooling of the convection caused due to the air circulating flow generated by disc rotation, it is necessary to provide a new structure for achieving the heat radiation or cooling of the heat generated from the laser element, through heat conduction into a mechanical chassis mounting thereon the optical pickup, etc.
[Patent Document 1] Japanese Patent Laying-Open No. 2005-310192 (2005)